Treatment Of Arrhythmias Research Articles

Cardiac Ablation in the Pediatric Population at a Tertiary Care Center in a Developing Country

ABSTRACTIntroductionThe aim of this study was to describe our experience and outcome of ablation therapy for arrhythmias in pediatrics at a tertiary care center.MethodsData was collected retrospectively from the hospital medical records. All pediatrics presenting to AUBMC between 2000 and 2020 who underwent cardiac ablation were included. The data collected included type of arrhythmia, ablation technique, age and weight at ablation, procedure complications, medications used, and outcome assessment.ResultsWe had 67 patients who underwent cardiac ablation. Of those, 60% were males with a mean age of 15 years. Structural heart disease was present in 6% of patients. Wolff‐Parkinson‐White syndrome (WPW) was most prevalent at 31%, followed by atrioventricular nodal reentrant tachycardia (AVNRT) at 24%, atrioventricular reentrant tachycardia (AVRT) at 16%, ventricular tachycardia (VT) at 10%, atrial fibrillation (AF) at 3%, and atrial tachycardia (AT) at 1%. The remaining 15% of patients presented with less common types of arrhythmias, including other supraventricular tachycardias (SVTs), retrograde dual atrioventricular nodal reentry, and premature ventricular contractions (PVC). Antiarrhythmic medications were started before the procedure in 59% of our population. Medication regimens postablation included beta‐blockers (68%), type 1c antiarrhythmics (25%), calcium channel blockers (3%), ivabradine (2%), and amiodarone (2%). The completed procedures showed a success rate of 93%.ConclusionAblation of arrhythmias in pediatrics is an effective procedure in the treatment of childhood arrhythmias. More studies are needed on cardiac ablation in this age group and those with structural heart disease in the Middle East region.

Atrial arrhythmia and heart failure in adult patients with congenital heart disease: a retrospective cohort study

BackgroundAtrial arrhythmias (AA) and heart failure (HF) are major causes of hospitalisation in adult congenital heart disease (ACHD). This study aimed to evaluate the temporal relationship between AA and HF...

Clinical case of successful treatment of focal ventricular arrhythmia in a patient with arrhythmogenic mitral valve prolapse

The problem of managing of patients with mitral valve prolapse and ventricular arrhythmias — arrhythmogenic mitral valve prolapse — is quite relevant in routine clinical practice, which led to the creation in 2022 of an expert consensuses on the management of such patients. Based on the criteria, it is possible to identify a group of people at high risk of sudden cardiac death and implement measures to prevent death. How to manage patients at moderate risk of sudden cardiac death remains unclear. A clinical case of successful treatment of ventricular arrhythmias in a patient with arrhythmogenic mitral valve prolapse is presented.

Ablation of tachyarrhythmias with zero fluoroscopy technique in patients under 18 years of age. 4-year follow-up

Abstract Introduction Arrhythmias occur in 5% of preschool patients, with an increased incidence in adolescence. Treatment of rapid arrhythmias or tachyarrhythmias may include ablation of the cardiac structures. Catheter ablation is the possibility of producing an injury to the endocardium by administering energy through the catheter in a limited and controlled way to those parts of the cardiac tissue where tachycardias are initiated and/or maintained, it is performed through a catheter connected to an energy source, which is introduced through arterial or venous lines. to the chambers of the heart. In recent years, different technological innovations have emerged aimed at better understanding and identifying the substrate of arrhythmia, thus facilitating catheter navigation and reducing the need for fluoroscopy. Different studies have shown that ablation without fluoroscopy is feasible, especially in the context of supraventricular tachycardia. Objective To describe the clinical characteristics of pediatric patients undergoing ablation with zero fluoroscopy in a pediatric hospital of the National Medical Center of the West (CMNO). Material and Methods descriptive and retrospective study, the clinical characteristics of 42 patients who were taken to arrhythmia ablation by zero fluoroscopy technique at the CMNO IMSS pediatric hospital for 4 years in the period from June 2019 to May 2023 were analyzed. Results A total of 42 patients, of which 55% were male, with a median age of 13 years with a range of 4 to 17 years, the median weight was 49 kg with a standard deviation of +- 19.5 kg. Of the arrhythmias treated, supraventricular tachycardia accounted for 97.6% of cases and ventricular arrhythmias for 2.4%. Of the supraventricular tachycardias, atrioventricular reentrant tachycardia accounted for 68.35%. 25 cases with a diagnosis of Wolff Parkinson White with 28% of the right lateral location, followed by the right postoseptal 24%. Structural heart disease was present in 31% of the cases, the most frequent being Ebstein's anomaly (41.7%). Immediate success rate was 97.3%, with recurrence in the first three months of follow-up of 5.4%. A Kaplan-Meier curve was performed, showing a success rate of 77.3% at 12 months of follow-up. No statistical significance was found in patients with congenital heart disease and recurrence, p=0.698 and with Fisher's exact test, p=0.530. Conclusion Ablation of cardiac arrhythmias in children under 18 years of age without the use of fluoroscopy is an effective procedure, obtaining an immediate success rate of 97.3% of patients, 77.3% of patients are free of recurrence one year after treatment. There was no statistical significance for patients with congenital heart disease who might have recurrence.

Preliminary results of the non-invasive cardiac radioablation for ventricular tachycardia study; an in silico dosimetric comparison of photon vs proton radiotherapy for ventricular arrhythmias

Abstract Background Stereotactic arrhythmia radio-ablation (STAR) has been proposed as an alternative treatment for refractory ventricular arrhythmias (VA) in patients who are unsuitable or refractory to standard catheter ablation (CA). It consists in the application of external beam radiotherapy in a single dose of 25 Gy to the target areas. Most of the STAR treatments performed so far used photon radiotherapy. As compared to photons, particle therapy with protons, based on its finite penetration depth in tissue, might have the potential to reduce the dose to surrounding healthy tissues thus lowering the risk of side effects. Purpose The purpose of this in silico simulation study was to evaluate the feasibility of STAR with protons in patients with VA and to compare the doses of the organs at risk (OARs) in photon and proton treatment plans. Methods 14 patients (11 males) candidates to standard CA for VA were enrolled. ECG gated CT scans in expiratory breath-hold, and standard electroanatomical mapping were performed in each patients to reconstruct a 3D bipolar voltage map and identify the ablation target. Based on the information obtained by the contouring of the ablation target three treatment plans were simulated: one with photons, and two with protons - with and without cardiac gating- to assess the doses at the OARs. Results The median age was 68.5 (63.25-71.5), all patients had a history of recurrent VA and the indication for treatment with CA. 7 patients had an ischemic cardiomyopathy, 4 an idiopathic cardiomyopathy and 3 ventricular ectopic beats without structural heart disease. The mean left ventricular ejection fraction was 40±11% and 8 out of 14 patients were ICD carriers. Both photons and protons treatment plans reached the goals for target coverage (25 Gy on 98% of the target volume). A statistically significant reduction in the mean maximum dose (Dmax) to some OARs was observed in proton compared to photon plans (see table 1). Specifically, the Dmax delivered to the mitral valve, vena cava, descending aorta, esophagus and to the lungs have been largely reduced with the proton plans. However, in some specific cases, a higher maximum dose was observed for protons in structures close or overlapping with the target, mainly due to the need of an additional margin in the treatment plan to account for proton range uncertainty. The use of cardiac gating did not show a significant dose reduction to OARs compared to the non-gated proton plan. Conclusion The preliminary results of our in silico simulation study suggest that STAR therapy with the use of protons might be associated with a significant dose reduction to the surrounding organs. Nevertheless, the choice of the best treatment should be evaluated on a case by-case strategy since some specific cases may be better suitable for photon treatment.Table 1

Treatment of Systemic Sclerosis Complicated By Cardiac Arrhythmia: A Case Report

Cardiac manifestations are occasionally observed in Systemic Sclerosis patients. Primary cardiac involvement may occur as a direct consequence of the disease. Arrhythmias are also thought to be a direct result from conduction system fibrosis. Early diagnosis and treatment of arrhythmia can be rewarding for this patient as if intreated may lead to a fatal outcome. Beta blockers used to treat arrythmia may worsen Raynaud’s symptom in systemic sclerosis. So there has been a controversy regarding the treatment of arrhythmia in Systemic Sclerosis. Here we are reporting a case of Systemic Sclerosis who presented with palpitation and digital gangrene. Her resting ECG showed multiple premature ventricular complexes whereas echocardiogram did not show any significant abnormality. Then She was treated with non-selective beta blocker without any progression of her Raynaud’s. For her digital gangrene, along with other conventional treatment (like nifedipine & tadalafil) she was treated with endothelin receptor antagonist (bosentan) and showed good response. J Dhaka Med Coll. 2023; 32(1) : 92-95

Dynamics of changes in heart rate, ST segment and T-wave on patients with ventricular rhythm disturbances on the background of type 2 diabetes mellitus according to the results of 24-hour cardiac monitoring

The aim of the study was to analyze the dynamics of heart rate, assess the morphogenesis of the ST segment and T wave in patients with ventricular arrhythmias associated with type 2 diabetes mellitus (type 2 DM) based on the results of daily cardiac monitoring against the background of two regimens of metabolitotropic treatment. The study included 133 patients with type 2 DM with ventricular arrhythmias. The inclusion criteria for the study were: moderately severe type 2 diabetes in the stage of sub-/compensation on the background of combined glucose-lowering therapy without insulin, the presence of ventricular arrhythmias of classes III–V according to Lown B. and Wolf M. (1971). By random sampling, patients were randomized into 3 observation groups, statistically homogeneous in age, sex, duration of the diabetic syndrome, classes of ventricular arrhythmias. Patients of the 1st group (n = 44) received amiodarone and beta-blocker. Patients of the 2nd group (n = 45) received the same antiarrhythmic treatment, but in combination with meldonium for 3 consecutive months with the next 3-month course repeated after 6 months. Representatives of the 3rd group (n = 44) received treatment with amiodarone, beta-blocker and trimetazidine of the same duration. 24-hour ECG monitoring was performed at baseline, 3 months later, and 1 year later. Statistica 6.0 software was used for statistical processing. The examination revealed tachycardia syndrome and signs of pain and painless myocardial ischemia. It has been established that ventricular arrhythmias in type 2 DM are of a secondary nature, largely dependent on ischemic manifestations. Trimetazidine compared with meldonium showed a greater anti-ischemic effect, which made it possible to obtain a better antiarrhythmic effect. Trimetazidine is considered as one of the justified components of the treatment of ventricular arrhythmias of ischemic origin in patients with type 2 DM.

Sotalol dosage advice in pregnant women for the treatment of fetal cardiac arrhythmias

Sotalol dosage advice in pregnant women for the treatment of fetal cardiac arrhythmias

Promising tools for future drug discovery and development in antiarrhythmic therapy.

Arrhythmia refers to irregularities in the rate and rhythm of the heart, with symptoms spanning from mild palpitations to life-threatening arrhythmias and sudden cardiac death (SCD). The complex molecular nature of arrhythmias complicates the selection of appropriate treatment. Current therapies involve the use of antiarrhythmic drugs (class I-IV) with limited efficacy and dangerous side effects and implantable pacemakers and cardioverter-defibrillators with hardware-related complications and inappropriate shocks. The number of novel antiarrhythmic drug in the development pipeline has decreased substantially during the last decade and underscores uncertainties regarding future developments in this field. Consequently, arrhythmia treatment poses significant challenges, prompting the need for alternative approaches. Remarkably, innovative drug discovery and development technologies show promise in helping advance antiarrhythmic therapies. Here, we review unique characteristics and the transformative potential of emerging technologies that offer unprecedented opportunities for transitioning from traditional antiarrhythmics to next-generation therapies. We assess stem cell technology, emphasizing the utility of innovative cell profiling using multi-omics, high-throughput screening, and advanced computational modeling in developing treatments tailored precisely to individual genetic and physiological profiles. We offer insights into gene therapy, peptide and peptibody approaches for drug delivery. We finally discuss potential strengths and weaknesses of such techniques in reducing adverse effects and enhancing overall treatment outcomes, leading to more effective, specific, and safer therapies. Altogether, this comprehensive overview introduces innovative avenues for personalized rhythm therapy, with particular emphasis on drug discovery, aiming to advance the arrhythmia treatment landscape and the prevention of SCD. Significance Statement Arrhythmias and sudden cardiac death account for 15-20% of deaths worldwide. However, current antiarrhythmic therapies are ineffective and with dangerous side effects. Here, we review the field of arrhythmia treatment underscoring the slow progress in advancing the cardiac rhythm therapy pipeline and the uncertainties regarding evolution of this field. We provide information on how emerging technological and experimental tools can help accelerate progress and address the limitations of antiarrhythmic drug discovery.

Radiation dose to the eye of physicians during radio frequency catheter ablation: a small-scale study.

Radio frequency catheter ablation (RFCA), a treatment for arrhythmia, requires a long fluoroscopy time that increases the radiation exposure dose to the physician, particularly to the lens of the eye. It is recommended that a lens-specific dosimeter such as DOSIRIS® is used to measure the dose to the lens. In this study, we investigated whether conventional glass badges can be used as an alternative to lens dosimeters. The doses to the lenses of two physicians (physician A, main operator; physician B, assistant; physician B was further away from the patient than physician A) were measured for 126 RFCA procedures performed over a 6-month period (fluoroscopy rate of 3.0 p/s with use of a ceiling-hanging shield). The cumulative value measured by a lens dosimeter attached to the inside of Pb glasses (0.07-mm dose equivalent) next to the left eye was 4.7mSv for physician A, and 0.8mSv for physician B. The reading on the glass badge worn on the left side of the neck was 4.7mSv for physician A and 1.3mSv for physician B. Lens dosimeter and glass badge values showed a good correlation for the left eye and left neck (r = 0.86, p < 0.01). We show that glass badges may be a viable alternative to lens-equivalent dosimetry when using low-pulse fluoroscopy and a ceiling-hanging shield.

9370 Thinking Outside the Box: A Rare Case of Using Plasmapheresis Treatment of Amiodarone-Induced Thyrotoxicosis in Preparation For CABG

Abstract Disclosure: K. Shaik: None. A. Kartoumah: None. J. Alsheikh: None. A. Nayeem: None. M.H. Horani: None. Introduction: Amiodarone, a standard treatment for arrhythmias, poses a risk of disrupting thyroid function and causing amiodarone-induced thyrotoxicosis (AIT). In critical cases where AIT is refractory to first-line treatment, plasmapheresis can be a vital option to rapidly lower thyroid hormone levels, which is essential for pre-surgical stabilization. This case report describes plasmapheresis in managing AIT in a patient undergoing coronary artery bypass grafting, highlighting its role in preventing potential thyrotoxic crises. Case Presentation: A 75-year-old male with a past medical history of diabetes mellitus, coronary artery disease, arrhythmias treated with amiodarone, and a ninety-pack-year history of tobacco presented to the ED with complaints of chest pressure and dyspnea. Initial troponin levels were normal at 24 ng/mL but trended upward toward 66 ng/mL. In the ED, he was not tachycardic and denied recurrent pain, fever, or chills. A CT angiogram of his chest showed no pulmonary embolus. The patient was found to have low TSH (0.005), and his T3 and T4 were both elevated (3.89/1.96, respectively), confirming thyrotoxicosis; however, he was negative for Graves’ disease. While in the hospital, his amiodarone was discontinued, and he was started on prednisone 10 mg for 14 days and methimazole 5 mg for 14 days. He was ultimately discharged on the same prednisone and methimazole regimen and told to follow up with outpatient endocrinology. However, the patient reappeared a week later with dyspnea on exertion; blood work performed after admission revealed a higher free T4 at 2.87. The patient was admitted, and angiography showed three-vessel disease; however, a coronary artery bypass graft (CABG) procedure was delayed over the concern of a potential thyroid storm. Thus, CABG was planned for when free T4 was less than 2, and the patient underwent two rounds of plasmapheresis, which initially decreased free T4 to 1.7 and finally to 1.4. Ultimately, a CABG was performed and well tolerated. Discussion: Amiodarone-induced thyrotoxicosis (AIT) poses a challenge in patient management, especially in patients requiring urgent surgeries. Plasmapheresis is shown to be a valuable option for rapidly lowering thyroid hormone levels and stabilizing the patient in the pre-operative stages. This case demonstrates the effectiveness of plasmapheresis in reducing free thyroxine levels, facilitating a safe and successful CABG. Due to its ability to quickly remove circulating thyroid hormones, plasmapheresis has excellent potential in managing refractory AIT. It is crucial to carefully time plasmapheresis relative to surgery and monitor for complications throughout. Further research is required to optimize proper plasmapheresis protocols in AIT. Conclusion: This case study highlights plasmapheresis as a promising adjunctive therapy in managing AIT and preventing potential thyrotoxic crises. Presentation: 6/1/2024

Unveiling the mystery of the female heart's rhythm: a look into gender inequalities in electrophysiology.

This review explores gender disparities in cardiac electrophysiology, highlighting differences in the electrical activity of the heart between men and women. It emphasizes the importance of understanding these variances for correct diagnosis and effective treatment of cardiac arrhythmias. Women show distinct cardiac characteristics influenced by sex hormones, affecting their susceptibility to various arrhythmias. The manuscript covers the classification, mechanisms, and management of arrhythmias in women, considering factors such as pregnancy and menopause. By addressing these gender-specific nuances, it aims to improve healthcare practices and outcomes for female patients with cardiac rhythm disorders.

In vitro characterization of radiofrequency ablation lesions in equine and swine myocardial tissue

Radiofrequency ablation is a promising technique for arrhythmia treatment in horses. Due to the thicker myocardial wall and higher blood flow in horses, it is unknown if conventional radiofrequency settings used in human medicine can be extrapolated to horses. The study aim is to describe the effect of ablation settings on lesion dimensions in equine myocardium. To study species dependent effects, results were compared to swine myocardium. Right ventricular and right and left atrial equine myocardium and right ventricular swine myocardium were suspended in a bath with circulating isotonic saline at 37 °C. The ablation catheter delivered radiofrequency energy at different-power-duration combinations with a contact force of 20 g. Lesion depth and width were measured and lesion volume was calculated. Higher power or longer duration of radiofrequency energy delivery increased lesion size significantly in the equine atrial myocardium and in equine and swine ventricular myocardium (P < 0.001). Mean lesion depth in equine atrial myocardium ranged from 2.9 to 5.5 mm with a diameter ranging from 6.9 to 10.1 mm. Lesion diameter was significantly larger in equine tissue compared to swine tissue (P = 0.020). Obtained data in combination with estimated wall thickness can improve lesion transmurality which might reduce arrhythmia recurrence. Optimal ablation settings may differ between species.

A Comprehensive Review on Stereotactic Arrhythmia Radioablation (STAR): Pioneering a New Era in Arrhythmia Management.

Stereotactic arrhythmia radioablation (STAR) is an innovative treatment modality that leverages advanced imaging techniques and focused radiation to target arrhythmogenic foci within the heart, offering a non-invasive alternative to traditional catheter ablation methods. Arrhythmias, characterized by irregular heartbeats, pose significant health risks, including heart failure and stroke, particularly among older adults. Traditional management approaches, such as pharmacological therapies and catheter ablation, often face efficacy, safety, and recurrence limitations. STAR addresses these challenges by utilizing high-precision stereotactic technology to deliver targeted radiation, minimizing damage to surrounding tissues while maximizing therapeutic effects. This review explores the mechanisms, clinical indications, procedural techniques, and outcomes associated with STAR. Recent clinical studies demonstrate that STAR provides comparable efficacy to catheter ablation, with a favorable safety profile, making it a promising option for patients who have not responded to conventional treatments. Integrating STAR into arrhythmia management protocols may enhance patient outcomes and reduce the burden of recurrent arrhythmias. As research in this field advances, STAR holds the potential to reshape the landscape of arrhythmia treatment, providing new hope for patients suffering from these complex conditions. This review aims to elucidate the significance of STAR in modern arrhythmia management and to encourage further exploration and clinical application of this pioneering technique.

Fully Implantable Wireless Cardiac Pacing and Sensing System Integrated with Hydrogel Electrodes.

Cardiac pacemakers play a crucial role in arrhythmia treatment. Existing devices typically rely on rigid electrode components, leading to potential issues such as heart damage and detachment during prolonged cardiac motion due to the mechanical mismatch with cardiac tissue. Additionally, traditional pacemakers, with their batteries and percutaneous leads, introduce infection risks and limit freedom of movement. A wireless, battery-free multifunctional bioelectronic device for cardiac pacing is developed. This device integrates highly conductive (160Sm-1), flexible (Young's modulus of 80kPa is similar to that of mammalian heart tissue), and stretchable (270%) soft hydrogel electrodes, providing high signal-to-noise ratio (≈28dB) electrocardiogram (ECG)recordings and effective pacing of the beating heart. The versatile device detects physiological and biochemical signals in the cardiac environment and allows for adjustable pacing in vivo studies. Remarkably, it maintained recording and pacing capabilities 31 days post-implantation in rats. Additionally, the wireless bioelectronic device can be fully implanted in rabbits for pacing. By addressing a major shortcoming of conventional pacemakers, this device paves the way for implantable flexible bioelectronics, which offers promising opportunities for advanced cardiac therapies.

Nuciferine analogs block voltage-gated sodium, calcium and potassium channels to regulate the action potential and treat arrhythmia

Dysfunction of the Nav1.5, Cav1.2, and Kv channels could interfere with the AP and result in arrhythmias and even heart failure. We herein present a novel library of nuciferine analogs that target ion channels for the treatment of arrhythmias. Patch clamp measurements of ventricular myocytes revealed that 6a dramatically blocked both the INa and ICa without altering the currentvoltage relationship (including the activation potential and peak potential), accelerated the inactivation of Nav and Cav channels and delayed the resurrection of these channels after inactivation. Additionally, 6a significantly decreased the APA and RMP without affecting the APD30 or APD50. The IC50 values of 6a against Nav1.5 and Cav1.2 were 4.98 μM and 4.62 μM, respectively. Furthermore, 6a (10 μM) blocked IKs, IK1, and Ito with values of 17.01 %±2.54 %, 9.09 %±2.78 %, and 11.15 %±3.52 %, respectively. Surprisingly, 6a weakly inhibited hERG channels, suggesting a low risk of proarrhythmia. The cytotoxicity evaluation of 6a with the H9c2 cell line indicated that this compound was noncytotoxic. In vivo studies suggested that these novel nuciferine analogs could shorten the time of arrhythmia continuum induced by BaCl2 and normalize the HR, QRS, QT and QTc interval and the R wave amplitude. Moreover, 6a dose-dependently affected aconitine-induced arrhythmias and notably improved the cumulative dosage of aconitine required to evoke VP, VT, VF and CA in rats with aconitine-induced arrhythmia. In conclusion, nuciferine analogs could be promising ion channel blockers that could be further developed into antiarrhythmic agents.

Radiation-associated cardiovascular disease in patients with cancer: current insights from a cardio-oncologist.

Radiation-associated cardiovascular disease (RACD), a complex disease characterized with pericarditis, myocardial damage, valvular heart diseases, heart failure, vasculopathy and ischemic heart disease, has a generally poor prognosis. While RACD may be acute, it often manifests in the late years or even decades following radiation exposure to the chest. With an increasing number of cancer survivors, RACD is likely to become an important issue in cardio-oncology. This review discusses pre-radiation therapy (RT) preparation, peri-RT patient management and long follow-up planning post-RT from a cardiology perspective. Additionally, a novel technique of stereotactic radiotherapy, which has been applied for the treatment of intractable cardiac arrhythmias, is presented. Appropriate patient examination and management during and after RT are essential to support patients undergoing cancer treatment to improve long life expectancy. A multidisciplinary team is needed to determine how to manage patients who receive RT to reduce RACD, to detect early phases of RACD and to provide the best treatment for RACD. Recent studies increasingly report advances in diagnosis using new equipment that has the potential to detect early phases of RACD, along with growing evidence for the optimal treatment for RACD. This review provides an overview of recent studies and guidelines to report on the latest findings, and to identify unresolved issues surrounding RACD that require validation in future studies.

Cardiac arrhythmias in adults with congenital heart disease

In patients with congenital heart disease, cardiac arrhythmias are complex and require athorough understanding of the anatomy, past surgical and interventional procedures, and the specific electric processes. Supraventricular tachycardias commonly present as emergency situations and should be treated immediately, particularly when there is an underlying complex malformation. Establishing sinus rhythm is usually superior to pure frequency control for hemodynamic reasons. Catheter ablation should be preferred over medical treatment, even though several procedures are often necessary. In addition, bradycardia is seen more frequently in congenital heart defects; this could be aggravated by antiarrhythmic drugs. There are significant differences between the indications and techniques used for pacemaker implantation in patients with congenital heart defects and those without. Patients with complex congenital heart diseases have an increased risk of thromboembolism; therefore, an individual and early indication for low-threshold oral anticoagulation is necessary; direct oral anticoagulants can also be used for this purpose. In risk stratification for sudden cardiac death, the principles of general guidelines are often not applicable, and individualized decisions are required. Recently, anew general risk score for congenital heart disease has been developed. The treatment of cardiac arrhythmias in patients with congenital heart disease should always be performed in close cooperation with specialized centers.

Einthoven's triangle adapted for horses: Proposal for the Delta configuration.

Reliable ECGs are crucial for diagnosing arrhythmias, yet a lack of standardization impedes arrhythmia diagnosis and treatment in horses. To objectively determine an optimal position of Einthoven's triangle for ECG recordings in horses at rest, which can form the basis for standardized ECG recording and improve diagnosis and treatment of arrhythmias. The study involved 72 healthy, warmblood horses aged between 3 and 20 years. In view of future 12-lead studies and vectorcardiography, requiring an orthogonal system, Einthoven's triangle was positioned around the heart, in the transverse plane. Therefore, 11 electrodes were placed encircling the thorax behind the olecranon, to construct triangles with a horizontal base. Electrocardiogram recordings from different triangles were analyzed. Signal processing involved filtering, R peak detection, and median complex generation. Principal component analysis (PCA) and Euclidean distance measures were employed for data analysis. The left mid-thoracic and ventral regions had high PCA scores, indicating high information content. Base-down triangles exhibited higher summed Euclidean distances, contributing to enhanced diagnostic capabilities. A base-down triangle, called "Delta (Δ) configuration" emerged as most informative, while meeting all criteria. The base-down "Delta configuration" is the optimal Einthoven's triangle adapted for horses, providing large amplitudes and potential to provide basic insights into the mechanisms and origins of cardiac arrhythmias. Because the Delta configuration is positioned in the transverse plane, it forms the ideal basis for 12-lead ECG recordings that provide vectorcardiograms in an orthogonal coordinate system. Standardizing electrode positioning could improve ECG data comparability in equine cardiology.

Comparative characteristics of patients with a combination of obstructive sleep apnea and paroxysmal atrial fibrillation in the groups of interventional and conservative treatment of arrhythmia

Aim. To compare the clinical characteristics of two groups of patients with a combination of obstructive sleep apnea (OSA) and paroxysmal atrial fibrillation (AF), undergoing conservative treatment for arrhythmia and after pulmonary vein isolation.Material and methods. The study included 362 patients with paroxysmal AF who underwent respiratory sleep monitoring.Results. A predominance of clinically significant OSA was revealed (moderate and severe — 37% and 29%, respectively), as well as a higher drug burden and comorbidity in the group of patients receiving drug treatment for AF. The threshold value of body mass index (BMI), at which a high risk of severe OSA was predicted, corresponded to class 1 obesity (BMI ≥31 kg/m2). The results obtained demonstrated an association between an increase in the left atrium anteroposterior size and the severity of OSA (4,1 [3,8-4,4] cm, r=0,28; p&lt;0,001), which may be due to cardiac structural remodeling in patients with a combination of paroxysmal AF and severe OSA.Conclusion. In a cohort of patients with paroxysmal AF, a high incidence of clinically significant OSA was revealed. In the group of patients with a combination of OSA and AF undergoing conservative treatment, more unfavorable cardiovascular characteristics and a more severe comorbid status were revealed compared to the group of patients undergoing surgical treatment.